Production of graphene using electromagnetic radiation

ABSTRACT

Methods for converting graphite oxide into graphene by exposure to electromagnetic radiation are described. As an example, graphene oxide may be rapidly converted into graphene upon exposure to converged sunlight.

CLAIM OF PRIORITY

This application is a divisional of and claims priority to U.S. patentapplication Ser. No. 13/226,321, filed Sep. 6, 2011, and entitled“Production Of Graphene Using Electromagnetic Radiation,” the disclosureof which is incorporated by reference in its entirety.

TECHNICAL FIELD

This application relates to graphene, and methods for its production. Inparticular, methods employing electromagnetic radiation to form grapheneare disclosed. In some embodiments, methods use focused electromagneticradiation for the conversion of graphite oxide to graphene.

BACKGROUND

Graphene is a two dimensional sheet composed of sp² carbon atomsarranged in a honeycomb structure having a single atom thickness.Multiple sheets may be layered one atop another. The prospectiveapplications for graphene are numerous due to its extraordinaryproperties including: high aspect ratio (length to thickness ratio),high young's modulus, high strength, and high thermal and electricalconductivity. However, the practical use of graphene in engineeringapplications demands massive production of high quality graphene.Conventional methods for preparing graphene are low-yielding, or usehazardous and costly chemicals, laborious methods, and/or hightemperature treatments. Accordingly, better, safer, economicallyfeasible, and higher yielding methods of producing graphene are needed.

SUMMARY

This disclosure is not limited to the particular systems, devices andmethods described, as these may vary. The terminology used in thedescription is for the purpose of describing the particular versions orembodiments only, and is not intended to limit the scope.

Methods using focused electromagnetic radiation for the conversion ofgraphite oxide to graphene are described herein. These methods allow forthe large-scale synthesis of graphene using a single-step approach,which may improve the availability and utility of graphene. Thesemethods are environmentally friendly, use low temperatures, and arerapid.

In some embodiments, graphite oxide may be converted into graphene byexposing the graphite oxide to electromagnetic radiation. In someembodiments, a method comprises contacting a first graphitic materialhaving a first conductivity state with focused electromagnetic radiationto convert the first graphitic material into a second graphitic materialhaving a second conductivity state, wherein the second conductivitystate is higher than the first conductivity state.

In some embodiments, a kit for converting a graphitic material includesan apparatus for generating electromagnetic radiation of a desiredintensity, a first graphitic material having a first conductivity state,and instructions for exposing the first graphitic material toelectromagnetic radiation to convert at least a portion of the firstgraphitic material into a second graphitic material having a secondconductivity state, wherein the second conductivity state is higher thanthe first conductivity state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart that illustrates an exemplary method forconverting graphite oxide into graphene, in accordance with anembodiment.

FIG. 2 is a collection of exemplary Raman spectra, in accordance with anembodiment.

FIG. 3 is a collection of exemplary X-ray difractograms, in accordancewith an embodiment.

FIG. 4 is a photograph of exemplary samples of graphite oxide andgraphene, in accordance with an embodiment.

FIG. 5 is an exemplary field emission scanning electron micrograph(FESEM) of graphene, in accordance with an embodiment.

FIG. 6 is an exemplary transmission electron micrograph (TEM) ofgraphene, in accordance with an embodiment.

DETAILED DESCRIPTION

Methods using focused electromagnetic radiation for the conversion ofgraphite oxide to graphene are described herein. These methods allow forthe large-scale synthesis of graphene using a single-step approach,which may improve the availability and utility of graphene. Thesemethods are environmentally friendly, use low temperatures, and arerapid, particularly when compared to conventional techniques. In someembodiments, graphite oxide may be converted into graphene by exposingthe graphite oxide to electromagnetic radiation. Graphene produced inthis manner may find applications in electrically conducting polymercomposites, advanced EMI shielding materials, nanofluidics, batteries,and environmental applications.

As used herein, “graphite oxide” refers to at least partially oxidizedgraphite, which may also be described as: graphitic oxide, graphiticacid, graphene oxide, or oxidized graphite nanoplatelets. Graphiticmaterials may be oxidized by numerous methods, and the specific methodor extent of oxidation is not intended to limit the scope of the currentapplication. Energy dispersive X-ray analysis spectra (EDX) may berecorded as a part of a field emission scanning electron microscopy(FESEM) experiment. In embodiments, graphite oxide may have an oxygencontent of about 25 weight percent, about 30 weight percent, about 35weight percent, about 40 weight percent, about 45 weight percent, or anyvalue in between.

As used herein, “graphene” typically refers to an allotrope of carbon,comprising single sheets or less than about 3 sheets of substantiallysp2-bonded carbon atoms. In embodiments, prepared graphene may be lessthan 100% carbon. In some embodiments, prepared graphene may have anoxygen content of about 4 weight percent or less. In other embodiments,graphene may have an oxygen content of about 0.01 weight percent toabout 10 weight percent, about 1.0 weight percent to about 6 weightpercent, about 2.5 weight percent to about 4 weight percent, or anyvalue or range of values in between. The remaining oxygen may be due tovarious sources such as —COOH and —OH molecules adsorbed on the surfaceof graphene.

Oxidation causes sp²-bonded carbon to become sp³-bonded, and may reducethe conjugation length of graphitic materials. Because a reducedconjugation length may decrease the electron mobility of a material,graphite oxide is typically considered an electrical insulator. Inembodiments graphite oxide may have electrical conductivity equal to orless than, about 10⁻¹ S/m, about 10⁻² S/m, about 10⁻³ S/m, or any valuein between. In other embodiments, graphite oxide may have electricalconductivity equal to or less than, about 10 ⁻³ S/m. Graphene, on theother hand, comprises substantially sp²-bonded carbon atoms and may haveextended conjugation lengths. In embodiments, graphene is an electricalconductor and may have an electrical conductivity equal to or greaterthan about 10 S/m, about 100 S/m, about 1,000 S/m, about 10,000 S/m, orany value in between. In some embodiments, graphene may have anelectrical conductivity equal to or greater than about 1,400 S/m.

Raman spectroscopy may be useful in the characterization of variouscarbon forms because the resulting spectrum may be sensitive to theelectronic structure of the material. Raman spectroscopy may be used todistinguish the nature of disorder in graphene and in graphite oxide.The Raman spectra of graphitic materials are generally characterized bytwo prominent features, (1) a G band at about 1567 cm⁻¹ due to firstorder Raman scattering of the E_(2g) phonon at the Brillouin zone centerof sp²-bonded carbon atoms, and (2) a D band at about 1356 cm⁻¹ arisingfrom the breathing mode of x-point phonons with A_(1g) symmetry atdefect sites. The Raman spectrum of graphite oxide typically displays anlarge broad D band at about 1368 cm⁻¹ and a large broad G band at about1604 cm⁻¹, and exhibits a shift to higher frequencies (blue shift) withrespect to that of graphite. The broadening and shifted frequency (about37 cm⁻¹) for the G band of graphite oxide may be attributed to thereduction in size of the in plane sp² domains due to oxidation ofgraphite. Referring to FIG. 2, the intensity ratio of the D band to theG band (I_(D)/I_(G)) for graphite (I_(D)/I_(G)˜0.07) is typicallyincreased to about 1.16 for graphite oxide, due to defects introduced bythe disruption of aromaticity caused by the presence of variousfunctional groups. In embodiments, a sharp G band (at about 1567.82cm⁻¹) and an I_(D)/I_(G) of about 0.20 for graphene may approximatethose of pure graphite. The decrease in I_(D)/I_(G) of graphene may bedue to the restoration of sp² network. In some embodiments, the Ramanspectrum of graphene may comprise bands at about 1360 cm⁻¹ and about1570 cm⁻¹ and the intensity of the band at about 1360 cm⁻¹ may be lessthan or equal to about half the intensity of the band at about 1570cm⁻¹.

Fourier transform infrared (FTIR) spectroscopy may be used tocharacterize the functional groups on a material. In embodiments, FTIRspectra show that graphite is essentially deficient of any functionalgroups except O—H stretching vibrations (at about 3427 cm⁻¹) whereasgraphite oxide may have one or more of the following functional groups:O—H stretching vibrations (at about 3432 cm⁻¹), CH₂ asymmetric andsymmetric stretching vibrations (at about 2924 cm⁻¹ and about 2852cm⁻¹), C═O stretching vibrations (at about 1825 cm⁻¹), C═C fromunoxidized sp² C═C bonds (at about 1627 cm⁻¹), O—H bending deformation(at about 1408 cm⁻¹) and C—O vibrations (at about 1049 cm⁻¹). Inembodiments, the FTIR spectra graphene may exhibit a broad O—H band (atabout 3436 cm⁻¹), which may be due to adsorbed moisture.

X-ray diffraction (XRD) may be used for the characterization of bondlengths and interlayer spacing of graphitic materials. The reflectionsfrom the C (002) plane of hexagonal graphite correspond to a peak with a20 value of about 26° in an XRD diffractogram. Interlayer spacing of theplanes in graphite may be increased from about 3.35 Å 305 to about 8.36Å in graphite oxide 310. Due to rapid heating of graphite oxide in thepresence electromagnetic radiation, the decomposition rate of theoxygen-containing groups of graphite oxide may exceed the diffusion rateof the evolved gases during this rapid heating process, yieldingpressures that exceed the van der Waals force holding the graphenesheets together in graphite oxide and lead to exfoliation of thegraphite oxide. In embodiments, the produced graphene shows a weak andbroader C (002) peak with a 20 value of about 20° to about 24° whichshows the exfoliation of graphite layers into a few layers of graphene315. Exfoliation may be observed as the volume of graphite oxide 405expands several fold upon conversion to graphene 410. FIG. 4 illustratesthe marked volume expansion of an approximately equal amount of graphiteoxide 405 and graphene 410. Referring to FIG. 5, a field emissionscanning electron micrograph (FESEM) demonstrates the expanded nature ofgraphene made by an embodiment. Referring to FIG. 6, a transmissionelectron micrograph (TEM) shows a single sheet of graphene made by anembodiment.

In some embodiments, the method comprises providing a first graphiticmaterial which is at least partially oxidized and has a firstconductivity state; and exposing the first graphitic material toelectromagnetic radiation to convert at least a portion of the firstgraphitic material to a second graphitic material having a secondconductivity state which is higher than the first conductivity state andwherein the electromagnetic radiation is incident on the first graphiticmaterial at an intensity that may be equal to or greater than about 1.1watts/cm². In other embodiments, the intensity of the electromagneticradiation incident on the first graphitic material may be between about0.5 watts/cm² and about 7 watts/cm², about 1 watt/cm² and about 5watts/cm², about 1.5 watts/cm² and about 3 watts/cm², or any value orrange of values in between.

In some embodiments, the first graphitic material is graphite oxide. Insome embodiments, the first graphitic material comprises at leastpartially oxidized graphitic materials selected from but not limited tographite oxide, graphitic oxide, graphitic acid, graphene oxide,oxidized graphite nanoplatelets, oxidized carbon nanotubes, oxidizedfullerenes, and combinations thereof.

In some embodiments, the second graphitic material is graphene. In someembodiments, the second graphitic material comprises graphitic materialscomprising substantially sp²-bonded carbon atoms, including but notlimited to: graphite, graphite nanoplatelets, carbon nanotubes, andfullerenes.

In some embodiments, the method comprises providing a graphite oxidehaving a first conductivity state; and exposing the graphite oxide toelectromagnetic radiation to convert at least a portion of the graphiteoxide into graphene having a second conductivity state, wherein thesecond conductivity state is higher than the first conductivity state,and the electromagnetic radiation is incident on the graphite oxide atan intensity that may be equal to or greater than about 1.1 watts/cm².In other embodiments, the intensity of the electromagnetic radiationincident on the graphite oxide may be between about 0.5 watts/cm² andabout 7 watts/cm², about 1 watt/cm² and about 5 watts/cm², about 1.5watts/cm² and about 3 watts/cm², or any value or range of values inbetween.

The resultant material has a higher conductivity state than the startingmaterial. That is, through electromagnetic radiation, the firstgraphitic material, e.g. graphite oxide, having a first conductivitystate is converted into a second graphitic material, e.g. graphene,having a higher, second conductivity state. In embodiments, the firstconductivity state may be equal to or less than, about 10⁻¹ S/m, about10⁻² S/m, about 10⁻³ S/m, or any value in between. In other embodiments,the first conductivity state may be equal to or less than, about 10⁻³S/m. In embodiments, the higher conductivity state of the secondgraphitic material is higher than the first conductivity state and maybe equal to or greater than about 10 S/m, about 100 S/m, about 1,000S/m, about 10,000 S/m, or any value in between. In some embodiments, thehigher conductivity state of the second graphitic material may be equalto or greater than about 1,400 S/m. In embodiments, dry graphite oxidemay be converted into graphene by exposure to electromagnetic radiation.Dry graphite oxide may be placed 105 in a suitable container prior toexposure to electromagnetic radiation. Suitable containers may include,but are not limited to; Petri dishes, beakers, flask, trays, or othercontainers in which the graphite oxide can be spread in a layer on thesurface.

In embodiments, the electromagnetic radiation may comprise one or morewavelengths from about 250 nm to about 2,500 nm. Specific examples ofwavelengths include about 250 nm, about 500 nm, about 750 nm, about 1000nm, about 1250 nm, about 1500 nm, about 1850 nm, about 2000 nm, about2250 nm, about 2500 nm, and ranges between any two of these values. Thesource of electromagnetic radiation may be sunlight, simulated sunlightor a non-natural source such as, but not limited to an incandescentbulb, a flash tube, a LED, a laser, an IR lamp, a Xenon lamp, a UVlamps, a laser and a High Intensity Discharge lamp, or combinationsthereof, selected portions thereof, or selected portions of combinationsthereof

In embodiments, the intensity of the electromagnetic radiation may beincreased by passing it through at least one refractile material priorto exposing the graphite oxide to the electromagnetic radiation. Theintensity of the electromagnetic radiation may be increased by passing110 it through at least one converging lens prior to the exposing step115. In embodiments, passing the electromagnetic radiation through arefractile material may increase the intensity by about 3,000 percent.In embodiments, the intensity of the electromagnetic radiationcontacting the graphite oxide may be greater than about 1.1 watts/cm².In other embodiments, the intensity of the electromagnetic radiationcontacting the graphite oxide may be between about 0.5 watts/cm² andabout 7 watts/cm², about 1 watt/cm² and about 5 watts/cm², about 1.5watts/cm² and about 3 watts/cm², or any value or range of values inbetween.

In other embodiments, the electromagnetic radiation may be syntheticallygenerated at the desired intensity or otherwise focused or concentratedto the desired intensity. In some embodiments, the electromagneticradiation may be concentrated by reflecting off of a converging mirror.

The exposure of graphite oxide to electromagnetic radiation may causerapid heating of the graphite oxide. The conversion of graphite oxide tographene by exposure to electromagnetic radiation may occur at lowtemperatures. In embodiments, exposure to electromagnetic radiation mayheat the exposed graphite oxide at a rate of about 100° C. per second.In embodiments, exposure to electromagnetic radiation may heat theexposed graphite oxide suddenly to between about 150° C. and about 200°C. over a time period of about 1 to about 2 seconds. After the initialheating period, the exposing step 115 may be maintained 120 at less thanabout 200° C. In some embodiments, the temperature of the exposing stepmay be maintained at less than about 100° C., about 175° C., about 250°C., about 350° C., about 500° C., or any value in between. In someembodiments, the temperature of the exposing step may be fluctuatebetween about 25° C. and about 1,000° C., about 100° C. and about 500°C., about 125° C. and about 250° C., about 150° C. and about 200° C., orany value or range of values in between. The conversion 125 of graphiteoxide to graphene by exposure to electromagnetic radiation may be rapid.In embodiments, the exposing step may be performed less than about 10minutes, less than about 5 minutes, less than about 2 minutes, or lessthan about 1 minute.

A low conductivity graphitic material may be converted into a highconductivity graphitic material by contacting the low conductivitygraphitic material with focused electromagnetic radiation. Inembodiments, the low conductivity graphitic material may be graphiteoxide or any other at least partially oxidized graphitic material. Inembodiments, the high conductivity graphitic material may be graphene orany other substantially sp²-bonded graphitic materials.

In an embodiment, a kit for converting low conductivity graphiticmaterial may be provided. The kit may comprise: an apparatus forgenerating electromagnetic radiation of a desired intensity; a lowconductivity graphitic material, and instructions for exposing the lowconductivity graphitic material to electromagnetic radiation to convertat least a portion of the low conductivity graphitic material into ahigh conductivity graphitic material.

The low conductivity graphitic material provided in the kit may compriseoxidized graphite or any other at least partially oxidized graphiticmaterial. In embodiments, the low conductivity graphitic material may beconverted into a high conductivity graphitic material comprisinggraphene or any other substantially sp²-bonded graphitic materials.

The apparatus for generating electromagnetic radiation provided in thekit may generate electromagnetic radiation comprising one or morewavelengths from about 250 nm to about 2,500 nm, about 200 nm to about400 nm, about 400 nm to about 780 nm, about 780 nm to about 10,000 nm,or any value or range of values in between with a desired intensity ofat least about 1.1 watts/cm². In some embodiments, the desired intensitymay be between about 0.5 watts/cm² and about 7 watts/cm², about 1watt/cm² and about 5 watts/cm², about 1.5 watts/cm² and about 3watts/cm², or any value or range of values in between.

The apparatus for generating electromagnetic radiation provided in thekit may comprise a converging lens arranged and configured toconcentrate a natural or artificial source of electromagnetic radiationto the desired intensity. The apparatus for generating electromagneticradiation provided in the kit may comprise a source of electromagneticradiation. The source of electromagnetic radiation may comprisesunlight, an incandescent bulb, a flash tube, a LED, a laser, orcombinations thereof

Embodiments illustrating the method and materials used may be furtherunderstood by reference to the following non-limiting examples.

EXAMPLES Example 1 Conversion of Graphite Oxide to Graphene with FocusedSolar Radiation

Graphite oxide (5 grams) was spread over a Petri dish and subjected tofocused solar radiation using a converging lens of 90 mm in diameter.Sunlight is made up of both visible and non-visible light spanning therange of about 250 nm to about 2500 nm. The measured power of thefocused radiation ranged from 1.77 W to about 2.03 W per cm². Thetemperature raised suddenly (in 1-2 seconds) from room temperature(about 25° C.) to between 150° C. and 200° C. Upon exposure to thefocused solar radiation, a popping sound was heard from the graphiteoxide. A color change from light brown to dark black was observed uponexposure to the solar radiation. The reaction was complete in less thanabout 5 minutes. The Raman spectrum of the product graphene had a D bandat 1360 cm⁻¹, a G band at 1570 cm⁻¹, and an I_(D)/I_(G) of 0.20—similarto graphite (I_(D)/I_(G)=0.07). The conductivity of the product graphenewas found to be 1.494×10³ S/m, also similar to that of graphite(conductivity ˜10 ⁵ S/m). For comparison, graphite oxide is insulating,with an electrical conductivity of 10⁻⁵ S/m. Atomic force microscopy(AFM) was used to determine the height profile of individual structures,and it was found that the product graphene was present as two stackedgraphene sheets with a height of about 0.9 to about 1.4 nm.

Example 2 Conversion of Graphite Oxide to Graphene with Artificial Light

Graphite oxide is spread over a flat surface and is subjected toemission from a 100W quartz tungsten halogen incandescent bulbconfigured to have a power of about 2 W per cm² and filtered with aband-pass filter transmitting between 580 nm and 700 nm. The temperatureof the graphite oxide quickly increases to about 175° C. and turns frombrown to black.

The illustrative embodiments described in the detailed description andclaims are not meant to be limiting. Other embodiments may be used, andother changes may be made, without departing from the spirit or scope ofthe subject matter presented herein. It will be readily understood thatthe aspects of the present disclosure, as generally described herein,may be arranged, substituted, combined, separated, and designed in awide variety of different configurations, all of which are explicitlycontemplated herein.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds, compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodimentsonly, and is not intended to be limiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “ asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). It will be further understood by those within the artthat virtually any disjunctive word and/or phrase presenting two or morealternative terms, whether in the description or claims, should beunderstood to contemplate the possibilities of including one of theterms, either of the terms, or both terms. For example, the phrase “A orB” will be understood to include the possibilities of “A” or “B” or “Aand B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” and the like include the number recited andrefer to ranges which can be subsequently broken down into subranges asdiscussed above. Finally, as will be understood by one skilled in theart, a range includes each individual member. Thus, for example, a grouphaving 1-3 substituents refers to groups having 1, 2, or 3 substituents.Similarly, a group having 1-5 substituents refers to groups having 1, 2,3, 4, or 5 substituents, and so forth.

1. An apparatus for producing graphene from graphite oxide, theapparatus comprising: a device configured to output electromagneticradiation and impinge the electromagnetic radiation on graphite oxidewith an intensity of about 0.5 watts/cm² to about 7 watts/cm² .
 2. Theapparatus of claim 1, wherein the electromagnetic radiation has one ormore wavelengths of about 250 nm to about 2,500 nm.
 3. The apparatus ofclaim 1, wherein the device configured to generate outputelectromagnetic radiation and impinge the electromagnetic radiation ongraphite oxide comprises a source configured to produce electromagneticradiation of an intensity of about 0.5 watts/cm² to about 7 watts/cm².4. The apparatus of claim 3, wherein the source configured to producethe electromagnetic radiation of an intensity of about 0.5 watts/cm² toabout 7 watts/cm² comprises an incandescent bulb, a flash tube, a LED, alaser, an IR lamp, a Xenon lamp, a UV lamp, a High Intensity Dischargelamp, or combinations thereof.
 5. The apparatus of claim 1, wherein thedevice configured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide with an intensity of about0.5 watts/cm² to about 7 watts/cm² comprises at least one apparatusconfigured to receive electromagnetic radiation from a source ofelectromagnetic radiation, and increase the intensity of theelectromagnetic radiation to impinge the graphite oxide with theelectromagnetic radiation of an intensity of about 0.5 watts/cm² toabout 7 watts/cm².
 6. The apparatus of claim 1, wherein the deviceconfigured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises a refractilematerial configured to concentrate a natural or artificial source ofelectromagnetic radiation to the intensity of about 0.5 watts/cm² toabout 7 watts/cm².
 7. The apparatus of claim 1, wherein the deviceconfigured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises a converging lensconfigured to concentrate a natural or artificial source ofelectromagnetic radiation to the intensity of about 0.5 watts/cm² toabout 7 watts/cm².
 8. The apparatus of claim 1, wherein the deviceconfigured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises a convergingmirror configured to concentrate a natural or artificial source ofelectromagnetic radiation to the intensity of about 0.5 watts/cm² toabout 7 watts/cm².
 9. The apparatus of claim 1, wherein the deviceconfigured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises at least one of arefractile material and a converging mirror configured to receivenatural sunlight, and concentrate the natural sunlight to impinge thegraphite oxide with an intensity of at least about 1.1 watts/cm².
 10. Akit for producing graphene from graphite oxide, the kit comprising:graphite oxide; and a device configured to output electromagneticradiation and impinge electromagnetic radiation having an intensity ofabout 0.5 watts/cm² to about 7 watts/cm² on the graphite oxide.
 11. Thekit of claim 10, wherein the device configured to output electromagneticradiation and impinge the electromagnetic radiation on graphite oxidecomprises a source configured to produce electromagnetic radiationhaving at least one wavelength of about 250 nm to 2,500 nm and theintensity of about 0.5 watts/cm² to about 7 watts/cm².
 12. The kit ofclaim 11, wherein the source configured to produce the electromagneticradiation comprises an incandescent bulb, a flash tube, a LED, a laser,an IR lamp, a Xenon lamp, a UV lamp, a High Intensity Discharge lamp, orcombinations thereof.
 13. The kit of claim 10, wherein the deviceconfigured to output electromagnetic radiation of and impinge theelectromagnetic radiation on the graphite oxide comprises at least oneapparatus configured to receive electromagnetic radiation from a sourceof electromagnetic radiation, and increase the intensity of theelectromagnetic radiation to impinge the graphite oxide with theelectromagnetic radiation of an intensity of about 0.5 watts/cm² toabout 7 watts/cm².
 14. The kit of claim 10, wherein the deviceconfigured to generate output electromagnetic radiation and impinge theelectromagnetic radiation on the graphite oxide comprises a refractilematerial configured to concentrate and focus a natural or artificialsource of electromagnetic radiation to the intensity of about 0.5watts/cm² to about 7 watts/cm².
 15. The kit of claim 10, wherein thedevice configured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises a converging lensconfigured to concentrate and focus a natural or artificial source ofelectromagnetic radiation to the intensity of about 0.5 watts/cm² toabout 7 watts/cm².
 16. The kit of claim 10, wherein the deviceconfigured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises a convergingmirror configured to concentrate and focus a natural or artificialsource of electromagnetic radiation to the intensity of about 0.5watts/cm² to about 7 watts/cm².
 17. The kit of claim 10, wherein thedevice configured to output electromagnetic radiation and impinge theelectromagnetic radiation on graphite oxide comprises at least one of arefractile material and a converging mirror configured to receivenatural sunlight, and concentrate the natural sunlight to impinge thegraphite oxide with an intensity of at least about 1.1 watts/cm².
 18. Agraphene having a conductivity state of greater than about 1,000 S/m, anoxygen content less than about 5% by weight, and capable of producing aRaman spectrum having bands at about 1360 cm⁻¹ and about 1570 cm⁻¹,wherein the intensity of the band at about 1360 cm⁻¹ is less than orequal to about half the intensity of the band at about 1570 c⁻¹.
 19. Thegraphene of claim 18, wherein the conductivity state is greater thanabout 1,400 S/m, and the intensity of the band at about 1360 cm⁻¹ isabout two-tenths of the intensity of the band at about 1570 cm⁻¹. 20.The graphene of claim 18, wherein the graphene is produced by exposinggraphite oxide to focused sunlight having an intensity of about 0.5watts/cm² to about 7 watts/cm².